Nowadays, with remarkable development of information and communication technology and semiconductor technology, spread and use of portable electronic devices rapidly increases and portable electronic devices are now very widely used. As a portable electronic device, a smart phone having various additional functions such as web surfing as well as communication information transmission and reception is widely used.
While such a portable electronic device exhibits the relatively same or more advanced performance as well as a function thereof, an entire size and design of the portable electronic device are an important factor for satisfying a consumer's desire, and for this reason, a producer of the portable electronic device seeks a small size and a thin thickness while implementing the same function or an advanced performance.
Particularly, as an antenna device, an external antenna device such as an initial rod antenna device or helical antenna device has been used, but when the portable electronic device drops, the external antenna device becomes a weakest portion and deteriorates portability and thus a built-in antenna device has been recently used.
In order to protect components mounted at the inside and the outside of the portable electronic device from an external impact and a friction, a portable electronic device cover has been widely used as an accessory. Nowadays, such a portable electronic device cover performs a function as an auxiliary battery for charging the portable electronic device as well as a function of protecting the portable electronic device from an external impact and enables the portable electronic device to perform a new function when mounting the portable electronic device cover in the portable electronic device.
However, despite the function of the portable electronic device cover, when the portable electronic device cover is mounted in the portable electronic device, a problem exists that the portable electronic device cover deteriorates a performance of an antenna device housed in the portable electronic device. For this reason, a producer of the portable electronic device designs the portable electronic device to maximize a radiation performance of the antenna device in a state in which the portable electronic device cover is not mounted in the portable electronic device. However, when the portable electronic device cover is mounted in the portable electronic device, a characteristic, for example, a resonant frequency band of the antenna device is changed due to the portable electronic device cover and thus a radiation performance of the antenna device may be deteriorated.
In order to solve the problem, conventionally, by providing a physical space by forming a groove at a portable electronic device cover surface that contacts with the portable electronic device and by separating the portable electronic device cover and the antenna device, a method of reducing an influence due to the portable electronic device cover has been used.